Fluid pressure actuator

ABSTRACT

An actuator including an actuation member at least partially defining a chamber and a fluid generating media disposed in the chamber. The fluid generating media includes a first electrochemical composition and a second electrochemical composition. The first and second electrochemical compositions are together electrochemically responsive to a first fluid for generating a second fluid. The actuation member is actuatable via a pressure of the second fluid. A method of controlling an actuator is also included.

BACKGROUND

Fluid pressure is utilized for powering actuators in a variety of industries. For example, fluid pressure is used ubiquitously in the downhole drilling and completions industry to shift sleeves, open and close valves, move tubulars, drive pistons, set seals, etc. Currently fluid pressure for downhole operational use is provided by pumping fluid downhole from surface. To this end, specific setting tools and pipeline are often required to be installed and a significant amount of fluid must be pumped downhole, as the entire length of the pipeline to the downhole location must be filled with the pressurized fluid. Due to the wide range of possible uses and the foregoing limitations in current systems, alternate systems for enabling timely, accurate, reliable, and controllable fluid pressure actuation are always well received.

SUMMARY

An actuator including an actuation member at least partially defining a chamber; and a fluid generating media disposed in the chamber and including a first electrochemical composition and a second electrochemical composition, the first and second electrochemical compositions together being electrochemically responsive to a first fluid for generating a second fluid, wherein the actuation member is actuatable via a pressure of the second fluid.

A method of controlling an actuator including exposing a fluid generating media to a first fluid, the media including a first electrochemical component and a second electrochemical component; reacting the first and second electrochemical components electrochemically together upon exposure to the first fluid for generating a second fluid with the media; and actuating an actuation member of the actuator with a pressure of the second fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

FIG. 1 is a schematic cross-sectional view of an actuator controlled by exposing a fluid generating media to a fluid;

FIG. 2 is a photomicrograph of a powder 110 as disclosed herein that has been embedded in an epoxy specimen mounting material and sectioned;

FIG. 3 is a schematic illustration of an exemplary embodiment of a powder particle 112 as it would appear in an exemplary section view represented by section 3-3 of FIG. 2; and

FIG. 4 is a schematic illustration of a second exemplary embodiment of a powder particle 112 as it would appear in a second exemplary section view represented by section 3-3 of FIG. 2.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.

Referring now to FIG. 1, a fluid pressure actuator 10 is illustrated having a piston 12 arranged in a housing 14 for performing some desired operation. In various embodiments the piston 12 could be arranged to shift a component, open or close a port or valve, activate or deactivate a tool, set a seal, pump a fluid, etc. It is also to be appreciated that other components could be substituted for the piston 12, and the piston 12 is given as one example only. For example, the piston 12 could be replaced by any combination of sleeves, plugs, rings, arms, levers, inflatables, or any other component which is activated, triggered, driven, influenced, controlled, or otherwise actuated by fluid pressure. Additionally, although the piston 12 is arranged to move axially, actuation with respect to any other direction, such as rotationally, radially, etc., is also accomplishable. Moreover, the pressure could be used not to move a component, but instead to dampen or prevent movement of a component, and these uses are to be understood as included in the meaning of the term “actuate” (or any form thereof), as used herein. For ease of discussion, the actuator 10 may be discussed herein as being installed in a downhole environment, although it is to be appreciated that the actuator 10 could have use in any other industry or application in which the generation of a fluid (e.g., hydrogen gas, as discussed below) and/or use of a resulting pressure of the generated fluid is desired.

A piston chamber 16 is located on one side of the piston 12 and filled with a fluid generating media 18. The fluid generating media 18 is selected as a material that is responsive to a fluid 20. By responsive it is meant that the media 18 will react, corrode, dissolve, disintegrate, degrade, or otherwise be consumed or removed due to exposure to the fluid 20, and as a result of chemical reactions between the fluid 20 and the media 18, produce additional fluid in the chamber 16. For example, in one embodiment the fluid 20 is a downhole aqueous fluid mixture and the media 18 comprises both electrochemically active metals having high standard oxidation potentials, e.g., Mg, Zn, Al, Mn, etc., and less electrochemically active metals, such as Ni, Fe, W, Co, etc. that are together electrochemically reactive in the presence of the fluid 20 for generating an actuation fluid. More particularly, and as is discussed in more detail below, the media 18 can take the form of controlled electrolytic metallic materials, which are highly tailorable to different rates of reaction (i.e., corrosion) depending on the particular compositions and materials used to form the material. It is to be appreciated that the fluid 20 can take the form of any combination of naturally present downhole fluids and those that are purposefully delivered or pumped to the actuator 10.

The fluid 20 is initially isolated from the media 18, e.g., via a fluid barrier or wall 22. The wall 22 fluidly seals the chamber 16 from the fluid 20 with the exception of a port 24 therein (or multiple ones of the port 24). Flow through the port 24 may be initially blocked, e.g., by a mechanism 26. The mechanism 26 is intended to temporarily prevent flow of the fluid 20 through the port 24 until some amount of time passes or event occurs, and can take various forms to this end, e.g., a timer, delay, fuse, etc. For example, in the illustrated embodiment the mechanism 26 takes the form of a plug 28 that, like the media 18, is responsive to the fluid 20 and will be removed by the fluid 20 after being exposed to it for some amount of time. For example, a plug made from a controlled electrolytic metallic material could be inserted into the port 24 and removed at a predictable rate by exposure to the fluid 20, based on a known or estimated composition of the fluid 20 and a tailored composition of the plug 28. In other embodiments, the plug 28 could be removed physically instead of chemically, the wall 22 could be provided with or as a movable mechanism for selectively blocking the port 24 and rotating, sliding, etc. to open the port, etc. The mechanism 26 could also include a clock or countdown timer that enables activation of such a movable mechanism after some amount of time. Additionally or alternatively, the mechanism 26 could include a sensor that actuates a movable mechanism after detection of a certain downhole condition, parameter, or value thereof (e.g., temperature, pressure, sound, etc.).

A check valve 30 is arranged in the port 24 of the illustrated embodiment for enabling the fluid 20 to flow into the chamber 16 after the mechanism 26 has been triggered (e.g., removed) to open the port 24. As noted above, the media 18 will generate an actuation fluid (e.g., hydrogen gas) upon exposure to the fluid 20, and the check valve 30 will also prevent the generated fluid from escaping the chamber 16 in order to maintain pressure in the chamber 16 for actuating the piston 12.

As noted above, in one embodiment the fluid to be generated by the media 18 is a gas, more specifically, hydrogen gas. Hydrogen gas is convenient in downhole use because it results from the exposure of many reactive metals, e.g., magnesium, aluminum, zinc, etc. to various downhole fluids. Although these metals are relatively highly reactive, the rate of hydrogen or other fluid generation upon contact with downhole fluids is too slow for many downhole actuation applications. Methods of creating materials with increased rates of dissolution or corrosion, and therefore fluid generation, particularly hydrogen generation, are taught by United States Patent Publication No. 2011/0135953 (Xu), which Publication is hereby incorporated by reference in its entirety. As discussed in the Xu publication, by forming particles having an electrochemically reactive nano-coating and an electrochemically reactive core, the rate of corrosion of the selected materials can be increased by literally hundreds of times, or tailored to any desired level therebelow. By increasing the rate of corrosion, e.g., by magnesium and similarly highly reactive metals, the rate of fluid generation, e.g., hydrogen generation, is correspondingly increased and therefore suitable for actuating the piston 12 of the actuator 10 or some other actuation member.

In one embodiment, the media 18 takes the form of a powder, e.g., a powder 110 in FIGS. 2-4, or a sintered compact made from the powder (further examples provided by the Xu publication incorporated above by reference). Referring to FIGS. 2-4, the powder 110 includes a plurality of metallic, coated powder particles 112. Each of the metallic, coated powder particles 112 of the powder 110 includes a particle core 114 and a metallic coating layer 116 disposed on the particle core 114. The particle core 114 includes a core material 118. The core material 118 may include any suitable material for forming the particle core 114 that provides an electrochemical reaction with a material 120 of the metallic coating layer 116, e.g., when exposed to brine or other suitable fluid. Suitable core materials 118 include electrochemically active metals having a standard oxidation potential about greater than or equal to that of Zn, including as Mg, Al, Mn or Zn or a combination thereof. As noted above, these electrochemically active metals are very reactive with a number of common wellbore fluids, including any number of ionic fluids or highly polar fluids, such as those that contain various chlorides. Examples include fluids comprising potassium chloride (KCl), hydrochloric acid (HCl), calcium chloride (CaCl2), calcium bromide (CaBr2) or zinc bromide (ZnBr2). For example, electrochemical reactions, e.g., galvanic or electrolytic corrosion, in the presence of brine, e.g., including KCl or other salts dissolved in an aqueous solution (KCl being typically present downhole in an approximately 3% concentration), will produce hydrogen gas. The electrochemical reactions may be accompanied by other fluid generating processes, such as by dissolving the reactive metals with acids, e.g., HCl. The core material 118 may also include other metals that are less electrochemically active than Zn or non-metallic conductive materials, such as graphite. The material 120 could be other electrochemically reactive metals having electrochemical potentials more positive than that of the core material 118.

In an exemplary embodiment of the powder 110, the particle core 114 includes Mg, Al, Mn or Zn, or a combination thereof, as the core material 118, and more particularly may include pure Mg and Mg alloys, and the metallic coating layer 116 includes Al, Zn, Mn, Mg, Mo, W, Cu, Fe, Si, Ca, Co, Ta, Re, or Ni, or an oxide, nitride or a carbide thereof, or a combination of any of the aforementioned materials as the coating material 120. Of course, the core material 118 could be alternatively selected as less active, with the material 120 having a more electrochemically negative potential. The core material 118 for the particles 112 in the media 18 could all be the same material, or a combination of different materials, and similarly, the material 120 of the coating layers 116 could all be the same material, or a combination of different materials, with electrochemical reactions occurring between particles of different compositions and/or between cores and coatings of different compositions but of the same particle.

With regard to the electrochemically active materials, these materials may be used as pure metals or in any combination with one another, including various alloy combinations of these materials, including binary, tertiary, or quaternary alloys of these materials. These combinations may also include composites of these materials. Further, in addition to combinations with one another, Mg, Al, Mn, Zn or other core materials 118 may also include other constituents, including various alloying additions, to alter one or more properties of the particle cores 114, such as by lowering the density or altering the dissolution characteristics of the core material 118. In an exemplary embodiment, the core material 118 will be selected to provide a core chemical composition and the coating material 120 will be selected to provide a coating chemical composition and these chemical compositions will also be selected to differ from one another. Differences in the chemical compositions of the coating material 120 and the core material 118 may be selected to provide different dissolution rates and selectable and controllable dissolution of the media 18 formed therefrom, making the media 18 selectably and controllably dissolvable.

Among the electrochemically active materials, Mg, either as a pure metal or an alloy or a composite material, is particularly useful, because of its high degree of electrochemical activity, since it has a standard oxidation potential higher than Al, Mn or Zn. Mg alloys include all alloys that have Mg as an alloy constituent. Mg alloys that combine other electrochemically active metals, as described herein, as alloy constituents are particularly useful, including binary Mg—Zn, Mg—Al and Mg—Mn alloys, as well as tertiary Mg—Zn—Y and Mg—Al—X alloys, where X includes Zn, Mn, Si, Ca or Y, or a combination thereof. These Mg—Al—X alloys may include, by weight, up to about 85% Mg, up to about 15% Al and up to about 5% X. The electrochemically active metals including Mg, Al, Mn or Zn, or combinations thereof, may also include a rare earth element or combination of rare earth elements. As used herein, rare earth elements include Sc, Y, La, Ce, Pr, Nd or Er, or a combination of rare earth elements. Where present, a rare earth element or combinations of rare earth elements may be present, by weight, in an amount of about 5% or less.

The particle cores 114 may have any suitable particle size or range of particle sizes or distribution of particle sizes. For example, the particle cores 114 may be selected to provide an average particle size that is represented by a normal or Gaussian type unimodal distribution around an average or mean. In another example, the particle cores 114 may be selected or mixed to provide a multimodal distribution of particle sizes, including a plurality of average particle core sizes, such as, for example, a homogeneous bimodal distribution of average particle sizes (as discussed more detail in the Xu publication, incorporated by reference above). The selection of the distribution of particle core size may be used to determine, for example, the particle size and an interparticle spacing 115 of the particles 112 of the powder 110. In an exemplary embodiment, the particle cores 114 may have a unimodal distribution and an average particle diameter of about 5 μm to about 300 μm, more particularly about 80 μm to about 120 μm, and even more particularly about 100 μm.

The particle cores 114 may have any suitable particle shape, including any regular or irregular geometric shape, or combination thereof. In an exemplary embodiment, the particle cores 114 are substantially spheroidal electrochemically active metal particles. In another exemplary embodiment, the particle cores 114 are substantially irregularly shaped ceramic particles.

The metallic coating layer 116 is a nanoscale coating layer for the particle cores 114. In an exemplary embodiment, the metallic coating layer 116 may have a thickness of about 25 nm to about 2500 nm. The thickness of the metallic coating layer 116 may vary over the surface of the particle core 114, but will preferably have a substantially uniform thickness over the surface of the particle core 114. The metallic coating layer 116 may include a single layer, as illustrated in FIG. 3, or a plurality of layers as a multilayer coating structure, as illustrated in FIG. 4. That is, the coating layer 116 in FIG. 4 includes two layers as the core material 120, with a first layer 122 disposed on the surface of the particle core 114 and a second layer 124 disposed on the surface of the first layer 122. The first layer 122 has a chemical composition that is different than the chemical composition of the second layer 124 for enabling further tailoring of the properties of the powder 110, e.g., different rates of dissolution of the media 18. In a single layer coating, or in each of the layers of a multilayer coating, the metallic coating layer 116 may include a single constituent chemical element or compound, or may include a plurality of chemical elements or compounds. Where a layer includes a plurality of chemical constituents or compounds, they may have all manner of homogeneous or heterogeneous distributions, including a homogeneous or heterogeneous distribution of metallurgical phases. This may include a graded distribution where the relative amounts of the chemical constituents or compounds vary according to respective constituent profiles across the thickness of the layer. In both single layer and multilayer coatings 116, each of the respective layers, or combinations of them, may be used to provide a predetermined property to the powder particle 112 or a sintered powder compact formed therefrom. For example, the predetermined property may include the bond strength of the metallurgical bond between the particle core 114 and the coating material 120; the interdiffusion characteristics between the particle core 114 and the metallic coating layer 116, including any interdiffusion between the layers of a multilayer coating layer 116; the interdiffusion characteristics between the various layers of a multilayer coating layer 116; the interdiffusion characteristics between the metallic coating layer 116 of one powder particle and that of an adjacent powder particle 112; the bond strength of the metallurgical bond between the metallic coating layers of adjacent sintered powder particles 112, including the outermost layers of multilayer coating layers; and the electrochemical activity of the coating layer 116.

It is to be appreciated that any number of layers may be included in various embodiments according to the current invention (as further discussed in the Xu publication incorporated by reference above). The thickness of the various layers in multi-layer configurations may be apportioned between the various layers in any manner so long as the sum of the layer thicknesses provide a nanoscale coating layer 116, including layer thicknesses as described herein. In one embodiment, the first layer 122 and outer layer (e.g., the layer 124 or some other layer depending on the number of layers) may be thicker than other layers, where present, due to the desire to provide sufficient material to promote the desired bonding of the first layer 122 with the particle core 114, or the bonding of the outer layers of adjacent powder particles 112, e.g., during sintering of a powder compact from the powder 110, or to further tailor the rate of dissolution of the powder 110 and therefore generation of a fluid by the media 18 upon contact with the fluid 20.

In view of the foregoing, it is to be appreciated that the timing, speed, and magnitude (force and/or distance) of actuation can be controlled by controlling the volume, surface area, composition, etc., of the media 18. As noted above, the timing of the reaction can be triggered by use of the mechanism 26 or some other timer, delay, clock, sensor, fuse, etc.

The speed of fluid generation by the media 18 can be increased by increasing the surface area of the media 18. That is, for example, forming the media 18 as powder, e.g., the powder 110, will generally increase the speed by which fluid is generated as there is more surface area to react with the fluid 20. Similarly, the media 18 can be formed as sintered or formed beads, pellets, or the like, if a moderate degree of speed is required, or as a single, relatively large compact if the speed of actuation is desired to be slower.

Furthermore, with knowledge of the chemical composition of the fluid 20, the initial volume of the chamber 16 and/or surface area of the piston 12 in the chamber 16, and a desired volume of the chamber 16 after actuation and/or desired actuation force to be exerted on the piston 12 and/or desired actuation distance for the piston 12 to travel, a volume and composition of the media 18 for generating a suitable amount of fluid can be calculated. For example, if hydrogen is desired to be produced, and it is known that the downhole fluids are a KCl brine (typically of about 3% concentration of KCl), then the known chemical reactions of the materials comprising the media 18, e.g., a controlled electrolytic metallic material including magnesium and other highly reactive metals, can be used to determining the proper amount of the media 18 to use given a desired amount of hydrogen generation desired. In this example, hydrogen generation will result from both the chemical reaction of magnesium (or other reactive metal) being exposed to water and the galvanic couplings formed between the differing electrochemical components of the media 18, e.g., the particle cores and coating layers of a controlled electrolytic material as discussed above, and will be governed by the following reactions: 2 H⁺+2 e→H₂ (cathodic partial reaction); 2 Mg→2 Mg⁺+e (anodic partial reaction); 2 Mg²⁺+2 H₂O→2 Mg²⁺+2 OH⁻+H₂ (chemical reaction); 2 Mg+2H⁺+2 H₂O→2 Mg²⁺+2 OH⁻+2 H₂ (overall reaction); and 2 Mg²⁺+2 OH→Mg (OH)₂ (product formation). The rate of hydrogen or other fluid generation may be increased or tailored by the presence of other chemical components or catalysts, such as acids, the combination and concentrations of materials forming the galvanic couplings, etc. In one embodiment hydrochloric acid (HCl) is included in the fluid 20, and hydrogen generation is further defined by the reaction: 2 Mg+2 HCl→2 MgCl+H₂. With respect to Mg, it has been found that including other elements, e.g., Fe, Ni, Cu, Co, etc., in a controlled electrolytic material, that the rate of corrosion of Mg, and therefore rate of production of hydrogen, can be increased significantly when the other element is present in as low of a concentration as 0.2% with respect to that of Mg. Of course, Mg, KCl, and HCl are given as examples only, and other materials, chemicals, concentrations, compositions, combinations, etc. for the media 18 and the fluid 20, could be utilized and behave according to other known reactions. According to these known chemical and electrochemical reactions for the various materials discussed herein for the media 18 and the fluid 20, the speed of the generation of hydrogen or other fluid can be tailored and the proper amount of the media 18 determined with respect to its composition and the composition of the fluid 20 for accurately, timely, and reliably actuating a tool, device, mechanism, etc., as discussed herein.

While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. 

What is claimed is:
 1. An actuator comprising: an actuation member at least partially defining a chamber; and a fluid generating media disposed in the chamber and including a first electrochemical composition and a second electrochemical composition, the first and second electrochemical compositions together being electrochemically responsive to a first fluid for generating a second fluid, wherein the actuation member is actuatable via a pressure of the second fluid.
 2. The actuator of claim 1, wherein the media comprises a controlled electrolytic metallic material.
 3. The actuator of claim 1 wherein the media comprises a plurality of powder particles, the first electrochemical composition comprises a plurality of particle cores and the second electrochemical composition comprises a plurality of coating layers, and each powder particle includes one of the particle cores and one of the coating layers disposed on the particle core.
 4. The actuator of claim 3, wherein the particle cores and the coating layers are each metallic materials, and the particle cores have an oxidation potential more negative than that of the coating layers.
 5. The actuator of claim 3, wherein the particle cores comprise Mg, Al, Zn, Mn, or a combination including at least one of the foregoing.
 6. The actuator of claim 3, wherein the coating layers comprise Al, Zn, Fe, W, Co, Ni, or a combination including at least one of the foregoing.
 7. The actuator of claim 3, wherein the particle cores have a diameter of about 5 nm to about 300 nm.
 8. The actuator of claim 3, wherein the coating layers have a thickness of about 25 nm to about 2500 nm.
 9. The actuator of claim 1, wherein the first electrochemical composition comprises a plurality of first powder particles, and the second composition comprises a plurality of second powder particles, the first and second powder particles comprising different electrochemical materials.
 10. The actuator of claim 1, further comprising one or more ports into the chamber.
 11. The actuator of claim 10, wherein a check valve is disposed each of the one or more ports for maintaining the pressure in the chamber in order to actuate the actuation member.
 12. The actuator of claim 10, further comprising a mechanism for selectively opening the one or more ports.
 13. The actuator of claim 12, wherein the mechanism is a plug that is removable upon exposure to the first fluid.
 14. The actuator of claim 13, wherein the plug is a timer or fuse used to control a timing of actuation of the actuator.
 15. The actuator of claim 13, wherein the plug comprises a controlled electrolytic metallic material.
 16. The actuator of claim 1, wherein the actuation member is a piston.
 17. The actuator of claim 1, wherein the first fluid is a downhole fluid.
 18. The actuator of claim 1, wherein the first fluid includes brine, acid, or a combination including at least one of the foregoing.
 19. The actuator of claim 1, wherein the second fluid is a gas.
 20. The actuator of claim 1, wherein the second fluid is hydrogen.
 21. A method of controlling an actuator comprising: exposing a fluid generating media to a first fluid, the media including a first electrochemical component and a second electrochemical component; reacting the first and second electrochemical components electrochemically together upon exposure to the first fluid for generating a second fluid with the media; and actuating an actuation member of the actuator with a pressure of the second fluid.
 22. The method of claim 21 further comprising setting a volume, a composition, or a combination including at least one of the foregoing of the fluid generating media for controlling an actuation speed, an actuation magnitude, or a combination including at least one of the foregoing of the actuator upon exposure of the fluid generating media to the first fluid. 